Textile fiber drafting element



. BUTADIENE- 7x ACRYLONITRILE COPOLXMER )vlm ul 6 TREATED wo NG Oct. 5,1948. J. w. BAYMILLER TEXTILE FIBER DRAFTING ELEMENT Filed Sept. 16'.1945 SURFACE Patented (let. 5, 1948 TEXTILE FIBER DRAFTING ELEMENT JohnW. Baymiller, Manheim Township, Lancaster County, Pa., assignor toArmstrong Cork Pennsylvania Company, Lancaster, Pa., a corporation ofApplication September 16, 1943, Serial No. 502,553 6 Glaims. (cl.19-131) Thi application is a continuation-in-part of my copendingapplication Serial No. 457,717, now abandoned, entitled Textile fiberdrafting elements and method of making the same, and filed September 9,1942.

This invention relates to drafting aprons, spinning rolls, drawingrolls, and the like used in the textile industry and commonly known astextile fiber drafting elements. The invention finds particularusefulness in the so-called long draft aprons used in the drafting offibers, particularly rayon, and in the spinning roll covers used indrawing fibers, such as cotton, rayon, and the like.

The invention will be described with particular reference to long draftspinning aprons but it is here pointed out that the invention is notlimited to aprons. Additionally, the example chosen for illustration isused in the drafting of rayon fibers since the invention finds unusualcommercial acceptability in that field. Here again, it is pointed outthe invention is not limited to textile fiber drafting elements for theprocessing of rayon. It contemplates all textile fiber draftingelements, regardless of the particular work performed or the type offibers operated upon.

The invention also includes a method of treating textile fiber draftingelements to improve their workingsurf aces.

synthetic rubber aprons have been tried on longer staple fibers, such asrayon, it has been found that the frictional resistance or grip of theapron surface is so great that a positive holding action is exertedagainst the drafting of the front rolls resulting in broken fibers, amutilated roving, and excessive waste which collects and falls into theroving, causing defective work. For these reasons, synthetic rubberaprons have been completely inoperative in many instances on long staplerayon. These results indicate that a similar action probably takes placein the processing of the shorter staple fibers such as cotton but to alesser degree. Improved results in the processing of such fibers shouldbe attained by my invention, although satisfactory operation is nowobtained on such short staple fibers with the synthetic rubber apronsnow available.

There has also been a noticeable tendency for the synthetic rubberaprons to be damaged or destroyed because of failure of the apron tomove freely over the stationary supporting bar in theWhitin-Casablancas, the Saco Lowell-Roth, and other similar systems; thephysical characterise tics of the inner surface of the aprons impairingtheir movement over the stationary surface under usual drafting tension.

In drawing textile fibers, one commonly employed machine is the drawingframe which inrolls arethe same as those used on a regular three-rolldrafting frame. However, in place of a pair of middle rolls to engagethe fiber under treatment, a pair of aprons is provided which reachesforward close to the nip of the front rolls. The back rolls and apronsserve to break draft the roving and the front rolls and apronspertensively of leather. Attempts have been made to utilize syntheticrubber aprons but acceptable 1 operation of these has been limitedlargely to the processing of the shorter staple fibers. when cludes aseries of spaced pairs of drawing rolls, the lower roll of each pairbeing in the form of a fluted metal roll. The upper rollof each pair incertain types of drawing frames has a resilient working surface and inmany such units the upper rolls are covered with cork composition,

leather, and synthetic rubber. Front rolls covered with these materialsgive considerable difficulty in operation due to the factthat fibers,

particularly rayon fibers, tend to stick to the rolls and "lap up on orwrap around the front roll. Synthetic rubber is especially susceptibleto "lapping up." This fiber drawing illustration has been given astypical of the problems involved in fiber drafting. The same or similardifllculties may be encountered in roving frames, spinning frames, andin worsted and woolen processing equipment as well as in other serviceswhere fiber drafting elements are used.

From the foregoing it will be clear that the use of synthetic rubbersurfaces in the drafting and spinning of textile fibers, particularlyrayon and similar long staple fibers, has met with limited success. Inthe case of aprons used in long drafting, the frictional qualities ofthe synthetic rubber aprons have been too great, resulting in breakingof the fiber and concomitant mutilated rovings, as well as damage ordestruction of the aprons due to impaired movement of the aprons overthe stationary supporting bars. In the case of drawing rolls, theproblem has been one of lapping up on the front roll due to excessiveamnity of the synthetic rubber for the fibers.

Synthetic rubbers are well suited in many re- It is an object of myinvention to provide a textile fiber drafting element possessing theforegoing desirable characteristics of synthetic rubbers and at the sametime possessing an improved working surface which overcomes thedifficulties heretofore encountered. Another object of my invention isto improve the inner synthetic rubber surface of'drafting aprons toprovide a surface which will permit unimpaired movement of the apronsunder usual drafting tension. It is a further object of my invention .toprovide a method whereby these desired surface chameteristics may beimparted to synthetic rubber textile fiber drafting elements.

The synthetic polymerization products of openchain aliphatic conjugateddlenes, particularly those having the formula H2C=CRCH=CH2, wherein R ishydrogen, a halogen, or a methyl radical, are useful in the practice ofmy invention for they respond well to my treatment. The polymerizationproducts of butadiene, chloroprene, and isoprene, such as polybutadiene,butadiene-acrylonitrile, butadiene-styrene, and butadiene-isobutylenecopolymers; polychloroprene; polyisoprene; and isoprene-acrylonitrilecopolymers, all have the formula H2C=CR'-CH=CH:, wherein R is as definedabove, and the polymerization products of this class of polymerizableopen-chain aliphatic conjugated dienes is preferred. w

, In the course of experimental work in connection with the manufactureof textile fiber drafting elements, I have discovered that thosevulcanized or unvulcanized synthetic polymerization products ofopen-chain aliphatic conjugated dienes which in their final form have acarbon to carbon bond may be treated with a free halogen, to therebychange the surface characteristics of the product. By such treatment,the surface characteristics of the product are materially altered, andimproved; all afilnity which would cause lapping up is eliminated; thefrictional characteristics of the surface are changed, resulting in asurface ideally suited for the long drafting of rayon and other fibersheretofore difficult to work; and all tendency for aprons to be damagedor destroyed because of impaired movement over the stationary supportingbars is eliminated. Drawing rolls produced from such composition andhaving the treated surface have been found to work satisfactorily onrayon and long staple cotton, while untreated rolls of the samecomposition operating in an adjacent frame have lapped up to a degreesufficient to make their use impracticable. Likewise, long 'draft apronsformed from such composition and so treated have been found to operateremarkably well on machines employing the Whitin-Casablancas long draftsystem without undue tearing or breaking the fibers, whereas untreatedaprons operating in an adjacent frame have proved inoperative on ny onfibers.

I will describe a long drafting apron produced in accordance with myinvention using a vulcanized butadiene-acrylonitrile composition as thebase. A composition may be formed from the following constituents:

In the foregoing example, butadiene-acrylonitriie copolymer is the basecomposition, sulfur is the vulcanizing agent, zinc oxide is anactivator,

the phenyl-beta-naphthylamine is an anti-oxidant, the dibutyl phthalateis a plasticizer, the stearic acid is also an activator and may beomit-' ted, and the benzothiazyl disulfide is an accelerator.

As will be more fully discussed, other synthetic polymerization productsmay be substituted for the butadiene-acrylonitrile copolymer and theproduct may be vulcanized or unvulcanized, depending upon the service tobe performed. As is obvious, the base composition may be compounded withvarious ingredients to produce a final product having the desiredphysical properties.

This material is formed into an apron in the desired manner, with orwithout a backing cloth, fabric, or reinforcing cord. A preferredpractice is to provide an inner layer of a polymerization product of anopen-chain aliphatic-conjugated diene into which a reinforcing cord isembedded and to superimpose a layer of a polymerization product of anopen-chain aliphatic conjugated diene thereover to constitute the outerportion. The whole is then cured and vulcanized. After curing andvulcanization, the outer surface is buffed to the desired fineness. Thisapron is found to have an outer working surface which in itself wouldnot be satisfactory for drafting long staple rayon. The apron thusformed is subjected to the action of a free halogen for a period of timesuiilcient to permit a chemical reaction to take place at the desiredsurfaces of the apron. Preferably, with drafting aprons both the innerand outer working surfaces are treated but either surface maybeselectively treated if this is desired.

As a specific example, the apron may be im- ,mersed in a water solutionof chlorine, the

strength of which is equivalent to 6 to 8 cc. of a tenth normal sodiumthio-sulfate solution, for a period of about twenty minutes. Thechlorine water may be prepared by .passing chlorine gas into water untilthe required strength is obtained, by acidifying a solution of achlorine compound such as sodium or calcium hypochlorite, an organicsolution of chlorine may be used, or any other means of getting freechlorine into contact with the surface of the polymerization product.The strength of the chlorine solution is not critical provided, of Ycourse, there is free chlorine present. The desired chemical reactionwill take place in a very weak solution or in a substantially saturatedsolution. The duration of the treatment is not critical but depends uponthe halogen used, the degree of unsaturation of the polymerizationproduct, the strength of the treating solu-- tion and other variablefactors.

After the twenty-minute immersion in the chlorine water, the apron isremoved and dried. If solutions of sodium or calcium hypochlorite havebeen used, it is advisable to wash the aprons after treating in order toremove any trace of deposited salts.

In place of chlorine, any other halogen may be used, such as fluorine,bromine or iodine. Fluorine is so chemically reactive that its use iscommercially impracticable and bromine and iodine are not as reactive aschlorine. Therefore, I prefer to use chlorine because'it is cheap,readily available, clean, light-colored, and sumciently active toproduce satisfactory results in a relatively short period of time.

The polymer unit of the butadiene-acrylonitrile composition referred toin the foregoing example has the following formula:

H H H H H H [-co=c-cc-c H H H CN I believe that upon treatment with ahalogen, the carbon to carbon double bond in the polymer is saturatedand the material at the surface which has been treated would have thefollowing It is recognized that vulcanization causes a modification ofthe polymer but I have found that the final effect of the halogentreatment is substantially the same when applied to the polymerizationproduct in either the vulcanized or unvulcanized state.

Other polymerization products which have the following chemical polymerformulas may be treated in accordance with this invention:

It will be observed that in each of the foregoing examples there is adegree of unsaturation represented by the carbon to carbon double bondand any synthetic polymerization product of an openchain aliphaticconjugated diene in which there is a substantial degree of unsaturation,represented-by carbon to carbon double bonds in the polymerizationproduct will be found to work satisfactorily. Of course, thosepolymerization products having a high degree of unsaturation will bemore reactive than those of a lesser degree of unsaturation. Where thedegree of unsaturation is low, it is desirable for best results toincrease the proportion of the conjugated diene in the copolymer.

In addition to the attack at the carbon to carbon double bond which isbelieved to constitute the major part of the reaction, there may also besome substitution of halogen for hydrogen but,

in any event, the flnal result is the production of a product having animproved surface for textile fiber drafting. It should be rememberedthat the foregoing polymer formulas each represent a single polymer unitand highly polymerized products having a high molecular weight with anunsaturated bond in the polymer units will possess a high degree ofunsaturation suflicient even after vulcanization to the desired degreeto be highly receptive to the halogenation treatment.

It wi1l be understood that this is purely a surface treatment and thatthe reaction does not take place throughout the entire thickness of theapron. If the fiber drafting unit is rebuifed after use, because ofwear, it will be necessary to retreat it in order to again provide thedesired surface.

I have established that the reaction which takes place and provides thedesired working surface is not an oxidation reaction which might beexpected in the treatment of such organic materials with halogen andwater. I have treated butadiene-acrylonitrile copolymers and otherpolymerization products having a high degree of unsaturation withhydrogen peroxide in ammonium hydroxide thereby liberating oxygen veryrapidly and have found no substantial difference in the surfacecharacteristics of the products so treated. On the other hand, I havetreated the same materials with an organic solution of chlorine such asan ethylene dichloride solution of chlorine thus eliminating all oxygenand have obtained the same results as when the materials were .treatedwith a chlorine water solution. This establishes that the reaction isnot an oxidation reaction but a halogenation reaction.

I have treated polymerization products which do not have the carbon tocarbon double bond and have found that no substantial change in thesurface characteristics occurs. For example, I have treated the materialknown as "Koroseal and having a polymer formula as follows:

The surface was not changed. Apparently, the reaction takes place onlywith those polymerization products having carbon to carbon double bondsor at least the reaction is sufliciently great to be important only insuch compositions.

In the attached drawing:

4 Figure 1 is a diagrammatic view illustrating a so-called long draftapron as employed in the Saco Lowell-Roth system;

Figure 2 is a similar view showing the Whitin- Casablancas system; and

Figure 3 is a perspective view showing an apron having inner and outerworking surfaces treated in accordance with my invention.

In both the Saco Lowell-Roth and Whitin- Casablancas systems asillustrated, the drafting aprons move over a stationary supporting bar.This bar is indicated at 2 in Figure 1 and at 3 in Figure 2. The apron 4in Figure 1 is driven by a roll 5 and a tension roll 6 and guide' roll'I are provided. The roving 8 is drafted between the pair of back rolls9, front rolls l0, and intermediate roll i I. The fiber is supportedduring draft- 7 ing by the apron 4 moving over the stationary supportingbar I and the driving roll I, drafting tension being supplied to theapron by the tension roll I.

In the Whitin-Casablancas system shown in Figure 2, the drafting isaccomplished between the pair of back rolls I 2 and front rolls II. Inthis system a pair of drafting aprons l4 and II is provided, the lowerapron II is driven by roll I and the upper apron is driven by frictionalen-' gagement with the lower driven apron. A guide roll I! is providedand this roll is weighted to obtain the desired pressure between theaprons. The roving i is supported and operated upon by the aprons movingover their stationary supporting bars 2 and rolls i0 and I1.

Figure 3 illustrates a typical drafting apronembodying my invention. Itconsists of an outer portion I8 of a synthetic polymerization product ofan open-chain aliphatic conjugated diene such as thebutadiene-acrylonitrile copolymer of the example previously referred toand an inner portion I! formed of the same composition and preferablhaving a helically disposed reinforcing cord embedded therein; In thisembodiment, both the inner and outer working surfaces are indicated ashaving been treated. Of course, with cots and other drafting elementswhere there is no problem of impaired movement only the outer workingsurface may be treated and in drafting aprons it may be desirable totreat but one of the surfaces, although the simplicity of the processwhere the article is immersed in the treating solution recommends itselffor most articles.

For most textile drafting purposes oil resistance is desirable in thedrafting element and, where this is a factor, the oil resistantpolymerization products, such as the copolymers of butadiene andacrylonitrile. isoprene and acrylonitrile, and polymerized chloroprenewill be generally preferred.

While I have illustrated and described certain preferred embodiments ofmy invention, it will be understood that the same may be otherwiseembodied and practiced within the scope of the following claims.

I claim:

1. A lap-resistant textile fiber drafting element having a fiber workingsurface comprising the reaction product of a free halogen and avulcanized synthetic polymerization product of -an openchain aliphaticconjugated diene, said polymerization product having carbon to carbondouble 2. A lap-resistant textile fiber drafting element having a fiberworking surface comprising the reaction product of free chlorine and avulcanized synthetic polymerization product of an openchain aliphaticconjugated diene, said polymerization product having carbon to carbondouble bonds, said fiber working surface being characterized by its lapresistance.

3. A lap-resistant textile fiber drafting element having a fiber workingsurface comprising the reaction product of a free halogen and avulcanized copolymer of butadiene and acrylonitrile, said fiber workingsurface being characterized by its working surface being characterizedby its lap resistance.

6. A lap-resistant textile fiber drafting element having a fiber workingsurface comprising the reaction product of a free halogenand avulcanized polymerization product of chloroprene, said fiber workingsurface being characterized by its lap rebonds, said fiber workingsurface being characterized by its lap resistance.

sistance.

JOHN W. BAYMILLER.

REFERENCES CITED The following references are of record in the file ofpatent:

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